The present invention relates to a portable tank having an improved bottom configuration. More particularly, the present invention relates to a shearing pattern with a crease break for the bottom of a portable tank having improved features with regard to manufacture and use of the tank.
Previous portable tank configurations are described, for example, in the following U.S. Pat. Nos.: 948,994 to Howland; 1,007,633 to Beaton; 1,647,900 to Carpenter; 1,802,426 to Hoyt; 3,379,329 to Bryans et al; 4,557,406 Olinger et al; 4,746,034 to Ata et al.; 4,782,973 to Wiese; 4,785,958 to Snyder; and 4,840,284 to Snyder. Problems encountered with previous tank configurations have included difficulty in obtaining complete drainage of the tank. Often, the solutions created have required complex bottom structures.
By the present invention, there is provided an improved tank configuration with regard to the bottom portion thereof, wherein a flat sheet metal blank has notched corners which are sealed, by welding or the like, after the side edges are broken by the use of die members to form the tank bottom sides. Two of the side edges are sheared at angles and, when broken and sealed at their common corner, cooperate with an upward crease break in the bottom portion to provide a tank bottom which slopes with complete drainage toward a drain hole. The drain hole is formed so as to have a partly tapered edge to optimize drainage. The tank construction of the present invention eliminates the need for a divergent gap to create the desired tank bottom drainage, as described in U.S. Pat. No. 4,785,958 to Snyder. By the present invention, commencing with a flat piece of metal such as stainless steel or aluminum, by proper shearing and breaking, a metal bottom head of any size may be obtained that will drain the liquid product from the head.
Accordingly, it is an object of the present invention to provide an improved tank bottom which combines the steps of shearing and breaking the side edges of the tank bottom with breaking the slope of the tank bottom so as to provide complete drainage to a corner portion of the tank bottom.
It is another object of the present invention to provide an improved tank bottom which eliminates the need for a divergent gap to create the desired tank bottom drainage.
It is a further object of the present invention to provide an improved tank bottom which may be utilized on standard or special size bases when desired and which provides excellent drainage and sanitary conditions for situations requiring complete drainage.
It is another object of the present invention to allow the fabrication of various depth pitched bottom heads.
It is still another object of the present invention to provide an improved tank bottom which requires minimum welding around the outlet area as is desired in the industry.
It is still a further object of the present invention to provide an improved tank bottom which does not require stamping or swedge pressing the head to a slope.